ELECTRICAL GURU

What is an article ? article was very important word in English and so is there knowledge articles are used before only nouns to limit or define their uses in the context of sentence.they impart effectiveness and accuracy to the nouns in fact article are used as demonstrative adjectives and determiners before nouns. There are two kinds of articles 1) indefinite articles (A, An) 2) definite articles (the)

Practice questions 1. The ratio of voltage and electric current in a closed circuit a. remains constant b. varies c. increases d. falls Ans-c 2. The curve representing ohm's law is a. sine function b. Linear c. a parabola d. a hyperbola Ans-b 3. The resistance of a conductor having length l area of cross section a and resistivity ρ is given as: a. ρa/l b. ρl/a c. ρla d. l/ρ Ans-b 4. The resistance of wire varies inversely as a. area of cross section b. length c. resistivity d. temperature Ans-a 5. Which of the following quantities are same in all parts of a series circuit? a. voltage b. power c. current d. resistance Ans-c 6. Which of the following statements is false in case of a series circuit? a. the voltage drop across each resister is same b. the current flowing through each resistor is the same c. applied voltage is equal to the sum of voltage drops across individual resistors are additive d.none Ans-a

ted across a resistor gives a value of 65 V but the expected value of resistor was 68 V. Then the absolute error and the relative accuracy of the measurement will be a. 3.2%, 96.8% b. 3.8%, 96.2% c. 4%, 96% d. 4.4%, 95.59% ANSWER: 4.4%, 95.59% 13)   Precision of an instrument is defined as a. Closeness of output to the true value b. Change in output for every change in input c. Degree of freedom from random errors d. Both (a) and (b) ANSWER: Degree of freedom from random errors 14)   An instrument with high precision implies a. High accuracy b. Low accuracy c. Does not imply anything about measurement accuracy d. None of these ANSWER: Does not imply anything about measurement accuracy 15)   Low accuracy measurements from a high precision instrument are normally caused by a. Bias in the measurement b. Human errors c. Instrumental defect d. Low temperature ANSWER: Bias in the measurement https://t.me/ElectricalGuru

RRB JE CBT-2 IMPORTANT QUESTION (1) The statement that is not true for a continuous time causal and stable LTI system is (A) Zeros of the system can lie anywhere in the s-plane (B) All the poles must lie within | s | = 1. (C) All the poles of the system must lie on the left side of the j? axis. (D) All the roots of the characteristic equation must be located on the left side of the jω axis ANSWER: All the poles must lie within | s | = 1. (2) Let v = 2x²y + 3y²z + 4z²x. The curl of the gradient of the scalar field v is (A) 0 (B) ∞ (C) 4ax + 6ay + 8az (D) None of the above ANSWER: 0 (3) On which factor the slip of an induction motor normally does not depend? (A) Shaft torque (B) Rotor speed (C) Core loss component (D) Synchronous speed ANSWER: Core loss component (4) For finding mutual inductance the bridge method that is commonly used is (A) Schering bridge (B) Heaviside Campbell bridge (C) Wein bridge (D) De sauty bridge ANSWER: Heaviside Campbell bridge (5) Which one of the following statement is true for a 4-point starter? A 4-point starter is used to start and control the speed of a (A) Dc compound motor (B) Dc series motor (C) Dc shunt motor with field weakening control (D) Dc shunt motor with armature resistance control ANSWER: Dc shunt motor with armature resistance control (6) The low-pass filter and high-pass filter are cascaded with each other. Cut-off frequency of low-pass filter and high-pass filter are 30Hz and 20 Hz respectively. The resultant system of filters will function as (A) An all-stop filter (B) An all-pass filter (C) A band-pass filter (D) A band-stop filter ANSWER: A band-pass filter (7) For the periodic waveform given below, the second harmonic component has amplitude of (A) 1 (B) 0 (C) 2/π (D) √5 ANSWER: 0 (8) Consider the figure given below. A source has a load line v + i = 100.The current through the resistance is (A) 150 A (B) 100 A (C) 50 A (D) 25 A ANSWER: 50 A (9) The base load power plants are (A) Nuclear, run-of-river and diesel (B) Nuclear and run-of-river (C) Run-of-river and pump storage (D) Pump storage and diesel ANSWER: Nuclear, run-of-river and diesel (10) Consider a transmission line that has a sending end voltage V. For a fixed value of complex power flow in such a transmission line, the real power loss will be proportional to (A) 1/V² (B) V (C) V² (D) 1/V ANSWER: 1/V² (11) Let Q be a (5 x 6) matrix. The rank of Q is 4. The statement, which holds correct for Q, is (A) Qt Q will be invertible (B) Q Q t will be invertible (C) Q will have four linearly independent rows and five linearly independent columns (D) Q will have four linearly independent rows and four linearly independent columns. ANSWER: Q will have four linearly independent rows and four linearly independent columns. (12) Let uniformly distributed random variable be X. X takes the values between 0 and 1. The value of E {X³} will be (A) 0 (B) 1 (C) 1/2 (D) 1/4 ANSWER: 1/4 (13) The firing angle of a single-phase fully controlled thyristor bridge ac-dc converter is 25 and an overlap angle is 10. The constant dc output current is 20 A. The fundamental power factor (displacement factor) at input ac mains is (A) 0.8 (B) 0.78 (C) 0.9 (D) 1.2 ANSWER: 0.78 (14) The system shown below is (A) Stable for input u1 but unstable for input u2 (B) Conditionally stable (C) Unstable (D) Stable ANSWER: Stable for input u1 but unstable for input u2 (15) An electrically short, medium and long line primarily depends on the (A) Power transmitted over the line (B) Nominal voltage of the line (C) Physical length of the line (D) Wavelength of the line ANSWER: Physical length of the line (16) Considering the cost and overall effectiveness, the circuit breaker that is best suited for capacitor bank switching is (A) Air blast (B) Vacuum (C) SF6 (D) Oil ANSWER: Vacuum (17) For the voltage u (t) = 3 + 4cos(3t), the RMS value is (A) √17 V (B) 3 V (C) 4 V (D) (3 + 2√2) V ANSWER: √17 V (18) Which one of the following statement ho

💡 IMPORTANT FOR RRB JE💡💡 🚆🚆🚇🚇🚝🚝 The coefficient of coupling is given by  a. M / √(L2L1) b. M / (L2 L1) c. √(L2 L1) / M d. (L2 L1) / M ANSWER: M / √(L2L1) 72)   If the magnetic field is stationary and the conductor is in motion then the emf induced is called  a. Dynamically induced emf b. Statically induced emf c. Self induced emf d. Mutually induced emf ANSWER: Dynamically induced emf 73)   Which among the following sentences is correct?  a. Lenz’s law is used to find the direction of induced current b. Fleming’s right hand rule is used to find the direction of induced current c. Fleming’s left hand rule is used to find the direction of force d. All of these ANSWER: All of these 74)   The induced emf sets up the direction of current in such a way that the magnetic field produced by it  a. Supports the cause producing it b. Opposes the cause producing it c. Increases d. Decreases ANSWER: Opposes the cause producing it 75)   When the flux crosses the air gap, it bulges outward at the ends of the air gap and the flux density in the air gap is reduced. This is known as  a. Leakage flux b. Fringing c. Relative permeability d. Magnetizing force ANSWER: Fringing 76)   According to the End Rule, the current directions when looked from one end of the coil if that end is South Pole and if the end is North Pole are  a. Both clockwise b. Anticlockwise, clockwise c. Clockwise, anticlockwise d. Both anticlockwise ANSWER: Clockwise, anticlockwise 77)   If two conductors carrying currents in opposite direction are placed parallel to each other then the magnetic field set up by the conductors  a. Attract each other b. Repels each other c. Perpendicular to each other d. Parallel to each other ANSWER: Repels each other 78)   When a solenoid attracts an iron bar,  a. They leave the south pole to go around to the north pole b. They leave the north pole to go around to the south pole c. They leave the north pole to go to infinity d. They leave the south pole to go to the infinity ANSWER: They leave the north pole to go around to the south pole 79)   The amount of flux density set up in the core is dependent upon  a. Current b. No. of turns, cross sectional area of core c. Materials of the magnetic core, length of core d. All of these ANSWER: All of these 80)   Permeability of a material is  a. Directly proportional to both flux density and magnetizing force b. Directly proportional to flux density and inversely proportional to the magnetizing force c. Directly proportional to the magnetizing force and inversely proportional to the flux density d. Inversely proportional to both flux density and magnetizing force ANSWER: Directly proportional to flux density and inversely proportional to the magnetizing force https://t.me/ElectricalGuru

The number of cycles of the induced emf per second is equal to  a. No. of cycles per revolutions x no. of revolutions per second b. No. of cycles per second x no. of revolutions per second c. No. of cycles per revolutions x no. of revolutions per hour d. No. of cycles per revolutions / no. of revolutions per second ANSWER: No. of cycles per revolutions x no. of revolutions per second 32)   The non salient pole type synchronous generator is driven by  a. Hydraulic turbines b. Diesel engines c. Steam engines d. All of these ANSWER: Steam engines 33)   In India, the synchronous generator generates  a. 11 kilo - volts b. 33 kV c. 66 kV d. Either (a) or (b) ANSWER: Either (a) or (b) 34)   The synchronous generator is also called an  a. AC generator b. Alternator c. DC generator d. Only (a) and (b) ANSWER: Only (a) and (b) 35)   From full load to no load, the change of terminal voltage is more in case of  a. Lagging power factor b. Leading power factor c. Unity power factor d. Both lagging and leading power factor compared to unity power factor ANSWER: Both lagging and leading power factor compared to unity power factor 36)   In a balanced 3-phase system, if one of the two wattmeter’s reading is negative then the  a. Reading should be taken as it is b. Reading should be taken after reversing the pressure coil c. Reading should be taken after reversing the current coil d. All of these ANSWER: Reading should be taken after reversing the pressure coil 37)   The two wattmeter method is applicable for  a. Only star connected system b. Only delta connected system c. Both star connected and delta connected system d. None of these ANSWER: Both star connected and delta connected system 38)   By using two wattmeter method, power can be measured in  a. 3 - phase, 2 - wire system b. 3 - phase, 3 - wire system c. 3 - phase, 4 - wire system d. All of these ANSWER: 3 - phase, 3 - wire system 39)   In delta connected system, the potential difference between line outers is  a. Equal to the phase voltage b. Greater than the phase voltage c. Less than the phase voltage d. None of these ANSWER: Equal to the phase voltage 40)   The expression for total power output of a delta connected system in terms of phase voltage and current is given by  a. 3VpIpcos∅ b. √3VpIpcos∅ c. 1/√ 3VpIpcos∅ d. 1/3 x VpIpcos∅ ANSWER: 3VpIpcos∅ https://t.me/ElectricalGuru

21)   Slip ring induction motor has  a. Low starting torque b. Medium starting torque c. High starting torque d. None of these ANSWER: High starting torque 22)   The frequency of rotor current in an induction motor is  a. slip times the frequency of stator current b. slip times the frequency of supply c. One by slip times the frequency of stator current d. One by slip times the frequency of supply ANSWER: slip times the frequency of supply 23)   Slip of an induction motor increases with  a. increase in current and decrease in torque b. increase in current and torque c. decrease in current and torque d. decrease in current and increase in torque ANSWER: increase in current and torque 24)   In an induction motor, rotor speed is always  a. Less than the stator speed b. More than the stator speed c. Equal to the stator speed d. None of these ANSWER: Less than the stator speed 25)   The frequency of the induced emf in an induction motor is  a. Greater than the supply frequency b. Lesser than the supply frequency c. Same as the supply frequency d. None of these ANSWER: Same as the supply frequency 26)   The efficiency of the transformer will be maximum when  a. Iron losses is equal to the twice of the copper losses b. Copper losses is equal to the twice of the iron losses c. Iron losses is equal to the copper losses d. All of these ANSWER: Iron losses is equal to the copper losses 27)   Copper losses is proportional to  a. kVA b. square of kVA c. cube of kVA d. none of these ANSWER: square of kVA 28)   If the transformer is loaded then the secondary terminal voltage falls for and rises for  a. Lagging power factor, leading power factor b. Lagging power factor, unity power factor c. Unity power factor, lagging power factor d. Leading power factor, lagging power factor ANSWER: Lagging power factor, leading power factor 29)   Efficiency of a transformer is maximum at  a. Leading power factor b. Lagging power factor c. Unity power factor d. None of these ANSWER: Unity power factor 30)   Copper losses occurs due to ohmic resistance in  a. Primary winding b. Secondary winding c. Both primary and secondary winding d. None of these ANSWER: Both primary and secondary winding https://t.me/ElectricalGuru

Lithium cells operates ranging from  a. -25 ° C to 25 ° C b. -50 ° C to 25 ° C c. -50 ° C to 75 ° C d. -75 ° C to 75 ° C ANSWER: -50 ° C to 75 ° C 12)   The positive plates of nickel iron cell is made up of  a. Nickel hydroxide b. Lead peroxide c. Ferrous hydroxide d. Potassium hydroxide ANSWER: Nickel hydroxide 13)   In lead acid accumulators, the container is filled with distilled water and concentrated sulphuric acid in the ratio of  a. 1 : 2 b. 2 : 1 c. 3 : 1 d. 1 : 3 ANSWER: 3 : 1 14)   The emf of the dry cell is about  a. 0 V b. 0.5 V c. 1 V d. 1.5 V ANSWER: 1.5 V 15)   In leclanche cell, anode is packed in a porous pot containing  a. manganese dioxide b. charcoal powder c. sulphur dioxide d. only (a) and (b) ANSWER: only (a) and (b) 16)   The handle of iron box is made up of  a. Bakelite b. Ebonite c. Chromium d. Only (a) and (b) ANSWER: Only (a) and (b) 17)   Heating element of electric iron box is an alloy of  a. Copper and nickel b. Nickel and cobalt c. Iron and magnesium d. Nickel and chromium ANSWER: Nickel and chromium 18)   Electric heaters is made up of  a. Chromed iron b. Brass c. Steel d. Both (a) and (b) ANSWER: Both (a) and (b) 19)   In telegraphic machine, the machine parts that sends the message and the machine parts that receives the message are  a. Morse key, Morse key b. Morse key, Morse sounder c. Morse sounder, Morse key d. Morse sounder, Morse sounder ANSWER: Morse key, Morse sounder 20)   Buzzer in principle is a bell  a. with hammer b. with gong c. with both hammer and gong d. without hammer and gong ANSWER: without hammer and gong https://t.me/ElectricalGuru

 RRB JE : BASIC ELECTRICAL ENGG. 1) Filters are used to convert  a. Pulsating dc signal into a pure dc signal b. Pure dc signal into a pulsating dc signal c. Pulsating dc signal into a pure ac signal d. Pulsating ac signal into a pure dc signal ANSWER: Pulsating dc signal into a pure dc signal 2)   The cut - in voltage for silicon and germanium are  a. 0.3 V, 0.3 V b. 0.3 V, 0.7 V c. 0.7 V, 0.7 V d. 0.7 V, 0.3 V ANSWER: 0.7 V, 0.3 V 3)   The P - type semiconductor impurities are also called as  a. Acceptor impurities b. Donor impurities c. Either (a) or (b) d. None of these ANSWER: Acceptor impurities 4)   In N - type semiconductor, the impurities added to a semiconductor are  a. Trivalent b. Pentavalent c. Monovalent d. Tetravalent ANSWER: Pentavalent 5)   Impurities are generally added in the pure semiconductor to  a. increase the number of electrons b. increase the number of holes c. increase their conductivity d. all of these ANSWER: increase their conductivity 6)   If induction motor is direct switched-on then it will develop  a. 1.5 times their full load torque b. 1.5 to 2.5 times their full load torque c. 2.5 times their full load torque d. 1.5 to 5 times their full load torque ANSWER: 1.5 to 2.5 times their full load torque 7)   In DOL fuses are provided to protect against a. Short circuit protection b. Over voltage c. Over current d. Over load ANSWER: Short circuit protection 8)   In four - point starter, the no volt release is connected across the  a. Supply line through a protective resistance b. In series with field circuit through a protective resistance c. Either (a) or (b) d. None of these ANSWER: Supply line through a protective resistance 9)   The overload release protects the motor against  a. Over voltage b. Over current c. Over load d. All of these ANSWER: Over load 10)   3 - point starter is used to start the  a. Series motor b. Shunt motor c. Compound motor d. Only (b) and (c) ANSWER: Only (b) and (c) https://t.me/ElectricalGuru

1)   What is the purpose of bedding on the underground cables? a. To avoid leakage of current. b. To protect the sheath against corrosion. c. To protect the sheath from mechanical injury due to armouring. d. Both (b) and (c) ANSWER: Both (b) and (c) 2)   Armouring is provided above the bedding. The armouring consists of one or two layers of which wire or tape? a. Galvanised steel wire b. Thin wires of copper c. Wires of aluminium d. Wire made of both copper and cadmium ANSWER: Galvanised steel wire 3)   Why are the inter sheaths in cables used? a. Provides proper stress distribution b. Minimises the stress c. Provides protection against moisture, current and voltage surges d. To improve the insulation ANSWER: Provides proper stress distribution 4)   A layer similar to bedding is provided on the armouring to protect the whole cable from all atmospheric conditions. Which layer is this? a. Insulation b. A layer of jute c. Serving d. Sheath ANSWER: Serving 5)   The thickness of insulation provided on the conductor in the cable depends on which among the following factor? a. Operating voltage b. Current to be carried c. Power factor d. Both (a) and (b) ANSWER: Operating voltage 6)   The insulation resistance of a cable of length 10 km is 1M Ω . For a length of 100 km of the same cable, what will be the insulation resistance? a. 1 M Ω b. 10 M Ω c. 0.1 M Ω d. 0.01 M Ω ANSWER: 0.1 M Ω 7)   What is the main drawback of using paper as the insulating material? a. Is hygroscopic b. Has poor dielectric strength c. Has a very low insulation resistivity d. Has high capacitance ANSWER: Is hygroscopic 8)   What is the limit of the conductor cross section when paper insulation is used? a. 50 mm2 b. 250 mm2 c. 600 mm2 d. 1200 mm2 ANSWER: 600 mm2 9)   What is the dielectric strength of impregnated paper? a. 30 kV/mm b. 20 kV/mm c. 15 kV/mm d. 5 kV/mm ANSWER: 30 kV/mm 10)   What is empire tape? a. Impregnated paper b. Vulcanised rubber c. Enamel insulation d. Varnished cambric ANSWER: Varnished cambric ELECTRICAL GURU Channel provides materials and guidance to crack all compititive exams of Electrical Engineering. GATE, ESE, RRB JE, SSC JE, STATE PSU India's first Ad-free channel Contact for quiries:- Admin👉 @electrical_guru electrical.guru@yahoo.com 👇👇👇👇 https://t.me/ElectricalGuru

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